You can also make aliases for existing commands. If you want ls to show colors by default, do:

alias ls='ls --color=yes'

These aliases can be put in your login script (.bash_profile or .profile depending on what shell you are using).

Alias with variables

You can not make aliases with variables. But you can make functions, having a function in your .profile/.bashrc will work just like an
alias. To use ssh to copy files to a location on a server you can use

Creating aliases on shell startup

You can have your aliases created anytime you open an instance of a
shell. If you are using bash, edit your ~/.bashrc file and add one
alias per line. Once you save and close the file, run this to load your
new aliases immediately:

source ~/.bashrc

Otherwise, the new aliases will load whenever you open a new instance of the shell.
Another place to put your aliases if you want them to be
system-wide for all users is in /etc/bashrc. To load those aliases, add
this line to ~/.bashrc